Check Orthogonality -- Select the "Compute/Orthogonality" menu item to show the orthogonality of the grid, then select the same menu item again to hide it. The orthogonality is represented by the largest deviation from a right-angle amongst the four corners of each grid cell, exclusive of vertices along the edge of the grid.

Show Spacers -- Select the "View/Spacers" menu item to hide the boundary points and reveal the interactive spacers.

Adjust Spacers -- Using mouse button #1, drag one of the spacers to a new location along its respective edge. Witness the grid lines rearranging themselves smoothly to mimic the separations of the spacers themselves. The spacers can be further manipulated through the "View/Spacer Count..." and "View/Spacer Setup..." menu items.

Projection -- Change the map projection to "Stereographic" in the "
(View)/Setup..." dialog. The center of projection can be modified, if needed, using the "Projection Center" sub-dialog. The default projection is "Mercator", with (0, 0, 0) as the parameters of its center. Both "Mercator" and "Stereographic" are "conformal" mappings; i.e., they preserve angles. The geographic graticule can be toggled into view with the "View/Show-Hide/Graticule" menu item.

Revert to Mercator Projection -- Hide the map grid, then change the map projection back to "Mercator", using the "View/Setup..." dialog, then zoom and pan as needed to bring the model grid into view.